Tropical Cyclone Activity in the Southern Hemisphere: February 2025

In February 2025, tropical cyclone activity surged in the South Pacific and Indian Ocean, with six storms engaged. Cyclones Alfred, Seru, and Bianca were notable in the South Pacific, while Honde and Garance posed risks in the Indian Ocean. The conditions stemmed from warm oceanic temperatures, signaling a possible increase in severe cyclone events this season.

In late February 2025, two distinct oceans experienced an unusual surge in tropical cyclone activity, with three storms in the South Pacific and a similar number in the adjacent Indian Ocean. A false-color image obtained by the VIIRS sensor on the NOAA-20 satellite on February 26 illustrated five tropical cyclones, showcasing infrared brightness temperature indications that differentiate cooler cloud formations from the warmer ocean surface beneath. Prior to this imagery, Tropical Cyclone Rae was diminishing east of the displayed area after causing significant rainfall in Fiji.

The South Pacific hosted Cyclones Alfred and Seru, with Seru intermittently reaching Category 1 on the Saffir-Simpson scale while remaining offshore Australia. Cyclone Alfred, also projected to stay at sea, presented hazards to southern Queensland’s coastal zones, escalating from Category 2 to a forecasted Category 4 by February 27, according to the Australian Bureau of Meteorology.

In the Indian Ocean, Cyclone Bianca had weakened to tropical storm status following a peak intensity of Category 3 the previous day, remaining at a safe distance from mainland Australia. Concurrently, Cyclones Honde and Garance emerged as greater threats, with Garance prompting the shutdown of Mauritius’s airport due to its anticipated approach, expected to escalate from Category 2 to Category 3 on February 27, bringing wind speeds of 190 kilometers (120 miles) per hour.

Meteorologists attributed the proliferation of these storms to elevated sea surface temperatures and weak wind shear conditions, linked to a persistent marine heatwave off Western Australia since September 2024. This trend was further exacerbated by unusually warm ocean temperatures observed in late February. The Australian Bureau of Meteorology indicated a heightened likelihood of severe tropical cyclones this season, as the cyclone season typically spans from November to April in the Southern Hemisphere.

In summary, late February 2025 witnessed a rare confluence of tropical cyclones in the South Pacific and Indian Ocean, with multiple storms impacting regional weather patterns. Key cyclones included Alfred, Seru, and Bianca in the South Pacific, alongside Honde and Garance in the Indian Ocean. Meteorological factors such as warm sea temperatures contributed to this cyclone proliferation, prompting warnings and preparations across affected areas.

Original Source: earthobservatory.nasa.gov